Australia
August 13, 2015

If you drop a piece of toast, it will land butter side down (the likelihood of this is proportional to the price of the carpet). If you drop a cat, it always lands on its feet. 

But if you strap a piece of toast to the back of a cat, butter side up, and drop the cat, now that is a paradox.

If we adopt harvest weed seed control to get on top of the wild radish seed bank, could we paradoxically select for early flowering and early shedding wild radish that can avoid harvest weed seed control, and create another problem?

Weeds can adapt to whatever we throw at them, not just herbicides. AHRI research by Dr Michael Ashworth found that after five generations of selecting for early flowering wild radish, the time to first flower was halved. Early flowering selection reduced the time from emergence to flowering from 59 days to 29 days.

So why has harvest weed seed control been so successful at smashing the wild radish seed bank in the field?

Firstly, the early flowering radish in this study weren’t competitive. They were short, stunted plants that weighed in at one fifth the weight of the control plants. 

Secondly (and more importantly) harvest weed seed control is used in combination with a range of other weed control practices, namely herbicides, crop competition, crop topping etc. 

The most important thing to do in weed control is to get as many hits at the weed as possible. 

Harvest weed seed control, if practiced in isolation, will likely fail, but when used in conjunction with other weed control practices, it is a very powerful and effective tool.

Website: http://www.ahri.uwa.edu.au/

Published: August 13, 2015